Typical electrosurgical procedures, such as cutting or cautery procedures, are performed with a handheld device which the user can manipulate and control as the RF energy is delivered to the electrosurgical, electrode in order to facilitate the creation of the desired effect at the electrosurgical electrode which performs the cutting or cautery procedure. As disclosed in U.S. patent application Ser. No. 10/714,126 issued to Marion, et al., it would be advantageous to have an automated method to evaluate effects at the electrode and to automatically adjust RF characteristics at the electrode based on such feedback. Such a feedback procedure is clearly preferred to a method that relies upon the user to sense and feel a change in cutting characteristics while cutting with the electrosurgical electrode. For example, different tissue impedances and cutting electrode contact areas affect the voltage and current required to cut and require adjustment to the RF power supplied to the electrode. To rely on the user's impression of the cutting quality to adjust cutting parameters would not be the most efficient way to optimize the cutting or cauterizing operation.
Furthermore, starting a cut is a different process than the actual cutting process and can require different control parameters than the cutting operation. Typical electrosurgical generator/electrode systems do not distinguish between starting a cut and cutting and do not provide different controls for these different modes of operation. It would therefore be advantageous to provide an electrosurgical electrode/generator system that does differentiate between the two aforementioned modes to provide desired control capabilities in each.
Another concern in RF electrosurgical electrode/generator systems is the different cutting characteristics required by different tissue types. For example, certain tissue types require high RF power outputs to efficiently cut the tissue. In particular, some tissue types require a high RF output voltage but do not require high average power to sustain cutting. Simply controlling the RF output voltage and current, however, is not sufficient to support all tissue types and combinations of tissue types. Further, more custom tailored controls are needed.
Leakage currents, inadvertent currents between an electronic device and earth ground, are a serious concern in RF devices such as an RF electrosurgical generator/electrode system. It would be desirable to prevent or at least mitigate such leakage currents. Since inadvertent contact between the patient and earth ground can cause undesirable leakage currents, it would logically be advantageous to provide an electrosurgical electrode/generator system with leakage path detection capabilities.
In summary, it would be desirable to provide an electrosurgical electrode/generator system capable of detecting the difference between cutting mode and a start-to-cut mode and providing separate controls and feedback systems in each mode. It would further be desirable to provide controls with novel and efficient telemetry systems that provide feedback and control of the cutting or cauterizing operation based upon monitoring characteristics at the electrode. It would further be desirable to mitigate leakage and to detect leakage paths when leakage does occur. The present invention addresses these and other needs.